Retribution of the Ancients, Phyrexian Altar, and Flayer of the Hatebound

Prerequisites

• Retribution of the Ancients on the battlefield
• Phyrexian Altar on the battlefield
• Flayer of the Hatebound on the battlefield
• Flayer of the Hatebound has no +1/+1 counters on it

Steps

1. Activate Phyrexian Altar by sacrificing Flayer of the Hatebound, adding
2. Flayer of the Hatebound dies, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it
3. Flayer of the Hatebound enters the battlefield, dealing damage equal to its power to any target
4. Activate Retribution of the Ancients by paying and removing a +1/+1 counter from Flayer of the Hatebound, giving any creature -1/-1 until end of turn
5. Repeat

Results

• Infinite damage
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers
• Reduce any number of target creatures' toughness to zero